<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <ul>
            <li v-for="item of arr" v-if="flag">{{item}}</li>
        </ul>
    </div>
</body>
<script src="./lib/vue.global.js"></script>
<script>
  const {createApp} = Vue;
  const app = createApp({
    data(){
      return {
        arr:['a','b','c','d'],
        flag:false
      }
    }
  })
  app.mount('#app')
</script>
</html>